2015 Hyundai Sonata vehicle speed control problems

“The engine light started to come on and go off and when I got the codes ran, it said something along the line of misfire. I had the spark plugs changed and I kept regular maintenance done on oil changes and tune ups. Now my engine is knocking and the vehicle is in limp mode.”

“My 2015 Hyundai Sonata has demonstrated multiple instances of unintended acceleration and braking failure: April 20, 2024 – While idling in a drive-thru line, the vehicle suddenly lurched forward without any attempt to accelerate and crashed into the vehicle in front of me. I was unable to stop it. This resulted in the other car being totaled. I took it to a Hyundai dealership afterward, but they found no definitive cause. April 4, 2025 – My daughter was driving and attempted to stop at a red light. Despite applying the brakes, the car did not stop and continued through the intersection, striking the door of another vehicle. May 12, 2025 – Today, while using cruise control set to 55 mph, the car began accelerating beyond the set speed without input. It appears the cruise control system is malfunctioning and not disengaging as expected. The vehicle currently shows no open recalls, but I found that similar issues were previously investigated under NHTSA action DP21003 for this model year. These incidents occurred months apart, but the behavior is consistent and extremely dangerous. I am requesting a formal investigation. The safety of my family and others on the road is at risk.”

“The contact owns a 2015 Hyundai Sonata. The contact stated while driving at an undisclosed speed, the accelerator pedal was depressed; however, the vehicle failed to accelerate as intended. In addition, the check engine warning light illuminated, and the vehicle lost motive power. The vehicle was towed to the dealer where it was diagnosed with engine failure. The contact was informed that the engine needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure; however, the engine replacement request was denied. The failure mileage was approximately 140,829.”

“My transmission literally went out once on me the SECOND DAY after I financed it. Now, less than a year later, it says I need to replace the transmission again. This is ridiculous.”

“Engine just stopped working. car stop running turned off in the middle of traffic in Dallas Tx. I took my car for an oil change the mechanic said he’s had plenty of 2015 sonata engines just give out and some catch a fire as well.It gave no warning and no smoke. This happened last week.”

“I am 86 years old. I bought the car brand new so I am the original owner. I have kept the car perfectly maintained and garaged from the day I bought it. My wife is also 86. She and I are the only ones that drive the car. To date, it has 73,822 miles on it. The main issue I am having is random, unpredictable stalling and hesitation when trying to accelerate. We have also had unintended acceleration. This always happens at the worst times which causes grave concern for our safety. We have taken the care to the dealership here in Cape Girardeau, MO called Chris Auffenberg Hyundai. They've charged me $130 only to tell me nothing is wrong. I have continued to try to work with them and they now have decided a new fuel pump will fix this which is $730. I have noticed there are already hundreds of complaints on the 2015 that all say they have the same exact issues I am having but this dealership doesn't seem to care. Here is what I have read. "The most common issue in the 2015 Sonata lies with its faulty throttle control system, which can cause stalling, hesitation, and even unintended acceleration. Currently, there is no fix from Hyundai." My dealership will not…”